Organic acid profiles of Australian stingless bee honey samples determined by ion chromatography.

Abstract

The aliphatic organic acid content in stingless bee honey (n=111) from five Australian stingless bee species (Tetragonula carbonaria, T. hockingsi, T. davenporti, Austroplebeia australis and A. cassiae) was examined, with honey sourced from both rural and urban sources. Analysis of the organic acids as their anions was achieved using ion chromatography with suppressed conductivity detection with quantitation using external standards. Gluconic acid was the predominant organic acid detected in all the stingless bee honeys, followed by acetic and lactic acids, with the latter dependent on the genera. One-way ANOVA and principal component analysis (PCA) confirmed distinctive differences between honeys by genera. Both gluconic acid and malic acid were significantly higher in A. australis honeys compared to T. hockingsi (P < 0.0001) and T. carbonaria (P < 0.0001). Acetic acid was significantly lower in A. australis honeys compared to T. carbonaria (P < 0.01) and T. davenporti (P < 0.01). Lactic acid was significantly higher in Tetragonula honey samples, with honeys of all 3 species of Tetragonula showing statistically significant differences to A. australis honey (P < 0.05). Tetragonula honeys varied in organic acid content according to honey botanical origin. Variation by species and habitat was assessed using chemometrics. This study provides the first extensive data to characterise this food and to help understand the contribution these organic acids make to the characteristic tangy taste and organoleptic properties of stingless bee honeys.